The remains of the Castle can be visited
Friedau Castle (Ruin) (Zizers)

The Friedau Ruin in Zizers, Canton Graubünden, is a remnant of a medieval castle. It stands at an elevation of approximately 542 meters above sea level and is now freely accessible, within a residential area.
History+
Excavations in 2002 revealed a Neolithic settlement here. Later, an early medieval manor house was built, which Otto the Great gifted to the Bishop of Chur in 955. In the mid-13th century, it was converted into the current castle tower. Bishop Volkard von Neuburg initiated its construction, which was completed under Bishop Heinrich von Montfort (1251–1272).
Source: Wikipedia · Licence: CC BY-SA 4.0
This description draws on the facts documented in the linked Wikipedia article; Wikipedia content is licensed under CC BY-SA 4.0. Wording and editing: Mobile History.
Location: 46.9342, 9.5628